U.S. patent number 4,098,211 [Application Number 05/732,654] was granted by the patent office on 1978-07-04 for bumper rings.
This patent grant is currently assigned to Regal Tool & Rubber Co., Inc.. Invention is credited to James H. Files, John M. Montague, Clarence T. Thomerson.
United States Patent |
4,098,211 |
Files , et al. |
July 4, 1978 |
**Please see images for:
( Certificate of Correction ) ** |
Bumper rings
Abstract
A bumper assembly for fending off vessels floating adjacent a
marine structure includes bumper rings having flat lower surfaces
and uniquely relieved upper outer surfaces. In a further aspect, an
assembly includes a spring support element at one end thereof.
Inventors: |
Files; James H. (New Orleans,
LA), Montague; John M. (Dallas, TX), Thomerson; Clarence
T. (Corsicana, TX) |
Assignee: |
Regal Tool & Rubber Co.,
Inc. (Corsicana, TX)
|
Family
ID: |
24944450 |
Appl.
No.: |
05/732,654 |
Filed: |
October 15, 1976 |
Current U.S.
Class: |
405/213; 114/219;
114/220; 267/140 |
Current CPC
Class: |
E02B
17/003 (20130101); E02B 3/26 (20130101); Y02A
30/30 (20180101); Y02A 30/36 (20180101) |
Current International
Class: |
E02B
17/00 (20060101); E02B 3/20 (20060101); E02B
3/26 (20060101); B63B 059/02 () |
Field of
Search: |
;114/219,220,267,266
;267/139,140 ;61/48 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Blix; Trygve M.
Assistant Examiner: Goldstein; Stuart M.
Attorney, Agent or Firm: Richards, Harris & Medlock
Claims
What is claimed is:
1. In a bumper for attachment to a stable structure for fending off
vessels floating adjacent thereto, the combination which
comprises:
(a) a rigid upright column; and
(b) an outer protective shield surrounding said column and of
material which is yieldable compared to the material of said column
wherein the outer protective shield comprises a plurality of
elastomeric bumper rings surrounding said column in a stacked
relationship, wherein the lowermost bumper ring surrounding said
column forms a spring means, the spring means comprising a spring
having as its center the center of said plurality of elastomeric
bumper rings, said spring means sized to receive and freely move on
said column for receiving and absorbing axially directed forces on
said outer protective shield.
2. In a bumper for attachment to a stable structure for fending off
vessels floating adjacent thereto, the combination which
comprises:
(a) a rigid upright column; and
(b) an outer protective shield surrounding said column and of
material which is yieldable compared to the material of said column
wherein the outer protective shield comprises a plurality of
elastomeric bumper rings surrounding said column in a stacked
relationship, wherein the lowermost bumper ring surrounding said
column comprises a spring means and includes a plurality of springs
spaced circumferentially around said lowermost bumper ring, said
spring means sized to receive and freely move on said column for
receiving and absorbing axially directed forces on said outer
protective shield.
3. In a bumper for attachment to a stable structure for fending off
vessels floating adjacent thereto, the combination which
comprises:
(a) a rigid upright column; and
(b) an outer protective shield surrounding said column and of
material which is yieldable compared to the material of said column
wherein the outer protective shield comprises a plurality of
elastomeric bumper rings surrounding said column in a stacked
relationship, wherein the uppermost bumper ring surrounding said
columms forms a spring means, the spring means comprising a spring
having as its center the center of said plurality of elastomeric
bumper rings, said spring means sized to receive and freely move on
said column for receiving and absorbing axially directed forces on
said outer protective shield.
4. In a bumper for attachment to a stable structure for fending off
vessels floating adjacent thereto, the combination which
comprises:
(a) a rigid upright column; and
(b) an outer protective shield surrounding said column and of
material which is yieldable compared to the material of said column
wherein the outer protective shield comprises a plurality of
elastomeric bumper rings surrounding said column in a stacked
relationship, wherein the uppermost bumper rings surrounding said
column comprises a spring means and includes a plurality of springs
spaced circumferentially around said uppermost bumper ring, said
spring means sized to receive and freely move on said column for
receiving and absorbing axially directed forces on said outer
protective shield.
Description
SUMMARY OF THE INVENTION
This invention relates to bumper rings for systems which fend off
boats and barges from stationary marine structures to which the
bumpers are attached, and more particularly relates to bumper rings
of unique construction.
BACKGROUND OF THE INVENTION
Offshore platforms which the present invention is designed to
protect are semirigid structures subject to damage by excessive
shock loading. As drilling progresses to deeper waters in more open
seas with the use of heavier supply boats and barges, it has become
necessary to develop better protective systems. Such systems are
generally attached to individual legs of the offshore platform. In
the past, it has been the practice to use cast-off vehicle tires,
usually large off-the-road or aircraft tires, mounted on a
supporting column next to the platform leg, as shown for instance
in Blackman U.S. Pat. No. 2,413,210 or Rolando, U.S. Pat. No.
2,952,979, the latter showing the practice of filling the tires
with cable or other material to prevent their excessive sagging or
collapse. Some special structures have been built for this purpose,
a shown for instance in Roach, U.S. Pat. No. 3,005,435 and Schwall,
U.S. Pat. No. 2,424,635. However, each has attendant drawbacks. The
cast-off vehicle tire systems involve the difficulty of finding a
plurality of tires of the same large size, as well as the problems
which arise when corded tires become waterlogged and sag. Moreover,
deflected vehicle tires exhibit very poor shock absorption
capabilities. Schwall, supra, resorted to making special rubber
bumper moldings for this purpose, but such bumpers are mounted in a
nonrotating manner and are therefore subject to early destruction.
Roach shows rotating cushions, but the use of axles and bearings
provides too fragile a structure to withstand open-sea
battering.
THE PRESENT INVENTION
In accordance with one aspect of the present invention, a stack of
specially shaped bumper rings having a common mounting axis are
supported top and bottom on a supporting frame. The supporting
frame includes a pipe column.
Specially shaped bumper rings have an inner diameter sized to
receive and freely move on the pipe column. The top and bottom
surfaces of the bumper ring are generally parallel to one another
and have a lower out facing cylindrical surface and an upper out
facing conical surface of about half the height of the ring. The
out facing cylindrical surface and the out facing conical surface
preferably are joined together by first and second arcuate zones,
respectively, where the arc radius of the second zone is larger
than the arc radius of the first zone.
In a further aspect the bumper ring stack includes a compressible
bumper ring for receiving and absorbing axially directed
forces.
DESCRIPTION OF THE DRAWINGS
The novel features believed characteristic of the invention are set
forth in the appended claims. The invention itself, however, as
well as further objects and advantages thereof, will best be
understood by reference to the following detailed description of
illustrative embodiments taken in conjunction with the accompanying
drawings, in which:
FIG. 1 is an elevation view showing an illustrative embodiment of
the bumper system of the present invention;
FIG. 2 is an elevation view of a second embodiment of the bumper
system of the present invention;
FIG. 3 is a full sectional view of a first embodiment of a bumper
ring;
FIGS. 4 and 5 are partial sectional views of other embodiments of a
bumper ring;
FIGS. 6, 7 and 8 are diagrammatic illustrations of bumper ring
deflection caused by forces imparted by a vessel;
FIG. 9 is an elevation view of a bumper spring;
FIG. 10 is a sectional view taken along the lines 10--10 of FIG.
9;
FIG. 11 is a sectional view of a bumper spring; and
FIG. 12 is a sectional view of a further bumper spring.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, a leg 6 of an offshore platform (not
shown) supports a bumper assembly 8. Bumper assembly 8 includes a
column 10 which supports a stacked series of elastomeric
cylindrical bumper rings 12 surrounding the column 10 and having
inner peripheries loosely fitted thereto so that the rings 12 can
freely rotate on the column 10. A lower stop plate 16 supports the
bottommost ring and the other rings stacked thereabove. Column 10
is coupled to the platform leg 6 by two shock cells 20 and 22.
Shock cell 20 comprises a short vertical cylinder 24, which is
welded to a short horizontal cylinder 26. Cylinder 24 is hollow
with the lower end thereof being cut on a taper to slope downwardly
and inwardly towards leg 6. The lower end 10a of pipe column 10 is
conical in shape so that it can be stabbed into cylinder 24.
Cylinder 26 is supported by an outer cylinder 28 through a
cylindrical rubber body 30, which is adhered to the inner surface
of cylinder 28 and the outer surface of cylinder 26. The end of
cylinder 26 opposite vertical cylinder 24 is closed by a plate
32.
Cylinder 28 is welded to a split cylinder clamp 34. Clamp 34
encircles and secures the shock cell 20 to the leg 6. The clamp 34
formed in two halves is to be secured to leg 6 by a series of bolts
36. Cylinder clamp 34 is provided lateral rigidity by beams 38. A
reinforcing ring 42 encircles the cylinder 28 at the open end and
functions to oppose forces applied for deflection of cylinder
26.
A stop plate 44 is welded inside cylinder 28. Plate 44 is mounted
to shear loose in response to unusual forces so that the cylinder
26 can continue its travel and further deflect the shock cell
20.
The upper end of column 10 is secured in a split cylinder clamp 60
having an integral cylinder 62 which is supported coaxially in an
outer cylinder 64 by a rubber cylindrical body 66. Rubber body 66
is adhered to the outer surface of cylinder 62 and to the inner
surface of cylinder 64. Cylinder 64 is secured to leg 6 by a
doublet half cylinder 68, which includes beams 70. Beams 70
strengthen and secure cylinder 64 to half cylinder 68. Shock cell
22 also includes a reinforcing ring 74 encircling cylinder 64 at
its open end. Reinforcing ring 74 performs a similar function as
reinforcing ring 42 of shock cell 20, opposing forces applied for
deflection of cylinder 62.
Shock cell 22 further includes a stop plate 76 which is
peripherally welded inside of cylinder 64. Stop plate 76 serves the
same function as stop plate 44 in shock cell 20.
By providing like shock cells 20 and 22 both at the bottom and the
top of column 10, energy absorption will be the same whether the
bumper array 12 is contacted by a boat near the upper end or near
the lower end. However, while providing this desirable reaction, it
is also desirable to avoid maintenance of any substantial static
load on shock cells 20 and 22. For this purpose, a tensile bearing
support anchor such as a chain 100 or the like, is connected to a
lifting eye 102 on the lower end of column 10 and extends upwardly
at an angle of approximately 15.degree. measured from column 10
where it is secured to an eyelet 104 attached to leg 6. The chain
100 may be covered by a rubber encasement 106. By this means the
static loads which would otherwise tend to cause the rubber bodies
30 and 66 to creep are substantially eliminated.
In FIG. 2, a second bumper assembly 200 is shown, with like
numerals being utilized for like and corresponding parts as in FIG.
1. An elbow 202 extends from the upper end of pipe column 10. Elbow
202 serves to prevent vessels from hanging up upon the top end of
pipe column 10. Bumper assembly 200 may be given static support by
flexible tension bearing anchor 206. Anchor 206 may comprise a
chain similar to chain 100 of FIG. 1. Chain 206 is connected to a
lifting eye 212 on the upper end of the elbow 212 and extends
upwardly at approximately a 45.degree. angle where it is secured to
an eyelet 214 attached to leg 6. It functions to relieve the static
loads on shock cells 20 and 22 and may be used in place of chain
100.
Referring to FIG. 3, bumper ring 12 is shown in full section. Ring
12 is formed of an elastomeric material such as rubber or the like,
and has an inner diameter sized to receive and freely move on
column 10 (FIGS. 1 and 2). Ring 12 has a top and bottom surface,
252 and 254, respectively, and an out facing cylindrical surface
256. Top surface 252 is joined to the out facing cylindrical
surface 256 along conical surface 258 by arcuate perimeters 260 and
262. The bottom surface 254 is joined to the out facing cylindrical
surfaces 256 by an arcuate perimeter 264. Typically ring 12 has an
outside diameter of 31 inches and a height of 9 inches, in which
case the radii of curved perimeters 264 and 262 would be about 2
inches and the radius of curved perimeter 260 would be about 4
inches. There results a sloping conical surface portion 258, having
an angle a, FIG. 3, of approximately 30.degree..
Referring to FIG. 4, a bumper ring 270 is shown in partial section
having the same general shape as the bumper ring 12 of FIG. 3.
Bumper ring 270 has a top and bottom surface 272 and 274,
respectively, and an out facing cylindrical surface 276. Top
surface 272 is joined along an out facing conical surface 278 to
the out facing cylindrical surface 276. Bumper ring 270 is composed
of a resilient material such as rubber or the like and includes
relief holes 280 molded from the bottom surface 274. Bumper ring
270 includes an antifriction layer 282 of material, such as for
example, urethane clad to the conical surface 278 and the out
facing cylindrical surface 276. Anti-friction layer 282 may be
bonded to the ring 270 as shown in FIG. 4 or may be bonded and
mechanically connected to the ring 270 using mechanical interlocks
284 and 286 of FIG. 5.
The advantages of bumper rings 12 and 270 will now be apparent when
considered in connection with FIGS. 2 and 6-8. Referring to FIG. 2,
a vessel 300 moored to an offshore platform in an open sea with an
impinging wave causes the vessel to experience sway, heave and roll
motions. These motions cause the vessel 300 to move laterally into
the bumper assembly 200. Rub rails 302 on the vessel may deflect
the bumper rings 12 horizontally inward as well as vertically up or
down before the vessel moves away from the bumper assembly 200.
FIG. 6 shows the rub rail 302 deflecting bumper ring 304 inwardly.
Bumper ring 304 is shown with squared corners. Such bumper rings
catch the rub rail 302 and are readily torn at the shoulder when
the boat moves downward. However, using the bumper rings 12, FIG.
3, movement of the rub rail 302 will not readily damage the bumper
rings 12. The rub rail tends to slide off because of the form of
curvature of the upper corner on the bumper ring. Bumper rings 12
are free to move vertically. Upward movement causes contact to be
made by the bumper ring 12 with the side of the vessel adjacent to
rub rails 302 when the vessel 300 moves vertically upward against
the rings adjacent rub rails 302. Bumper rings having the
configuration shown in FIGS. 3-5 provide particularly high
performance and exhibit long life relative to prior rings. The
protective coating of FIGS. 4 and 5 serves further to lower the
frictional force impressed on the bumper rings and minimize
wear.
Bumper assembly 200, FIG. 2, includes a support spring unit 350.
Spring unit 350 is shown as the lowermost element surrounding the
pipe column 10. Spring unit 350 is compressible. It may include a
plurality of spring sections or interior cavities which permit
compression, allowing the stack of bumper rings 12 to move
downward. Freedom of movement thus provided prevents stress from
increasing when rub rail 302 exerts downwardly directed vertical
forces against the bumper rings 12.
FIGS. 9-12 illustrate embodiments of a compressible spring 350.
FIGS. 9 and 10 illustrate a particular bottom spring unit 360 in
the form of a cylinder about twice the height of rings 12. A
plurality of vertical slots 362 are formed in a rubber or urethane
body 364. The slots are shown slanted at an angle of approximately
10.degree.. However, the slots may be vertical, i.e., perpendicular
to the upper and lower surfaces 366 and 368, respectively, of
spring 360. As the boat of FIG. 2 rides downwardly, spring unit 350
compresses or collapses thereby minimizing the destructive forces
on the rings in contact with rub rails 302.
FIG. 11 illustrates a second embodiment of a support spring unit.
Spring unit 370 includes a plurality of slim coil springs 372
spaced circumferentially within a resilient body structure 373.
Coil springs 372 are of diameter smaller than the wall thickness of
body 373. Springs 372 preferably will be cast in body 373 at
uniform spaced locations around ring 370. Springs 372 in
conjunction with body 370 provide support for the normal weight of
the stack of rings 12 of FIGS. 1 and 2 and yet will yield in
compression under vessel imposed loading.
FIG. 12 illustrates a further embodiment of a support spring unit.
Spring unit 374 includes a single large diameter coil spring 376
cast in ring body 375 to provide static load support yieldable to
downward forces produced by vessel loading. While only one spring
ring unit 350 is shown in FIG. 2, it will be understood that two or
more spring ring unit may be employed.
It will now be appreciated that the rings 12 may be made buoyant so
that they would rise to the top. In such case, the spring 350, FIG.
2, would be located at the top of the stack.
Having described the invention in connection with certain specific
embodiments thereof, it is to be understood that further
modifications may now suggest themselves to those skilled in the
art and it is intended to cover such modifications as fall within
the scope of the appended claims.
* * * * *